Hello, I previously held my CISSP when I worked as a Government Contractor. I Then had some health issues and ended up at a different firm and my CISSP was not a requirement. Its been several years now (like 7) and I am loking to take the exam gain..
So Honestly, and since I am stil activly in the security field (just for financial firms instead of DoD now) I believe just a book to refresh for the CBK would suffice. Back when I did take the exam originally I took a bootcamp and used the Shon Harris book.. not sure if this is even relevant any longer as a prep guide..
Personally, the best materials are the official materials. I found the Official Study guide to be the most helpful, even though it takes quite a bit of time to get through.
However, he biggest thing that helped IMHO is all the tests and practice questions - specifically Sybex (Wiley / Official Guide) and the Official Practice Tests. CISSP for Dummies also had questions, and you can get even more if you buy All-in-One.
There are quite a few online offerings available (Surepass, Boson). However, I didn't need any of those to pass, so can't speak to them.
You can read more about my entire experience if you'd like for more context.
Hope that helped. Good luck!